1. Field of the Invention
This invention relates to a gas discharge display apparatus having a phosphor layer which generates visible light upon excitation by vacuum ultraviolet light.
The present application claims priority from Japanese Applications No. 2006-092054, the disclosure of which is incorporated herein by reference.
2. Description of the Related Art
Typically, a surface-discharge-type alternating-current plasma display panel (hereinafter referred to as “PDP”), which is of a gas discharge display apparatus, includes two opposing glass substrates placed on either side of a discharge space. On one of the two glass substrates a plurality of row electrode pairs, which extend in the row direction, are regularly arranged in the column direction and covered by a dielectric layer. On the dielectric layer a protective layer formed of magnesium oxide which is formed by a vapor deposition technique. On the other glass substrate, a plurality of column electrodes extending in the column direction are regularly arranged in the row direction, thus forming discharge cells arranged in the matrix form in positions corresponding to the intersections between the row electrode pairs and the column electrodes in the discharge space.
Phosphor layers, to which the primary colors, red, green and blue are applied, are formed in the respective discharge cells. Conventionally, (Y, Gd)BO3:Eu is known as a red phosphor, (Ba, Sr, Ca)MgAl10O17:Mn as a green phosphor, and BaMgAl10O17:Eu as a blue phosphor.
The discharge space of the PDP is filled with a discharge gas consisting of a gas mixture of neon and xenon.
The PDP initiates a reset discharge simultaneously between the row electrodes in each row electrode pair, and then an address discharge selectively between one of the row electrodes and the column electrode. The address discharge results in the distribution, over the panel surface, of light-emitting cells having the deposition of the wall charge on the dielectric layer adjoining each discharge cell, and no-light-emitting cells in which the wall charge has been erased from the dielectric layer. Then, a sustaining discharge is produced between the row electrodes of the row electrode pairs in the light-emitting cells. The sustaining discharge results in the emission of vacuum ultraviolet light from the xenon included in the discharge gas filling the discharge space. The vacuum ultraviolet light in turn excites the phosphor layer, whereupon the red, green and blue phosphor layers emit visible light to generate a matrix-display image on the panel surface.
In a PDP of such a structure, the protective layer formed of magnesium oxide and deposited on the dielectric layer overlying the row electrode pairs has the function of protecting the dielectric layer from ion impact and the function of emitting secondary electrons into the discharge space.
For this reason, in the conventional PDP provided with a protective layer having a high degree of the secondary-electron emission function for the purpose of a reduction in discharge voltage, when the application of a sustaining pulse causes a sustaining discharge in a lot of the light-emitting cells at approximately the same time, a large amount of electric current flows momentarily, thus increasing the discharge intensity. As a result, the luminance voltage residual image increases, and also degradation in the display quality, such as a reduction in the panel life, may possibly be caused.
It is a technical object of the present invention to solve the problems associated with the conventional gas discharge display apparatus as described above.